Complexes of Cu(II) Ions and Noncovalent Interactions in Systems with L-Aspartic Acid and Cytidine-5'-Monophosphate

Table 5

Differences between C₍₁₎ NMR and C₍₄₎ NMR chemical shifts for the ligands in the Cu(II)/Asp and Cu(II)/Asp/CMP systems in relation to metal-free systems [ppm].

Systems	Asp					CMP
	pH	^13C	^31P	C(1)	C(2)	C(2)	C(4)	C(5)	C(6)	C(5^′)	P
Cu(II)/Asp	3.0	1.536	0.129	0.122	1.163	—	—	—	—	—	—
	5.5	0.050	0.070	0.020	0.050	—	—	—	—	—	—
	8.0	0.595	0.602	0.169	0.755	—	—	—	—	—	—
Cu(II)/Asp/CMP	3.0	1.371	0.460	0.147	1.094	0.463	0.528	0.075	0.085	0.057	0.166
	4.5	0.069	0.643	0.113	0.080	1.042	0.932	0.052	0.047	0.051	0.080
	6.0	0.769	0.782	0.142	0.809	0.486	0.772	0.062	0.046	0.076	0.190
	8.0	0.809	0.749	0.152	0.689	0.860	0.858	0.071	0.064	0.062	0.129